Based on

Movies like Siberian Express (1996)

On the last leg of of a train ride from Moscow to Manchuria during the early years of World War Two, one of the passengers suddenly disappears. All of the other passengers, including military personnel and civilians from both the Axis powers and Allied nations, have reasons to be suspected. As the remaining passengers investigate, more murders are committed, until at last the political and personal motives of the killer (killers?) are unravelled.